Rotary drum drier



Feb. 9, 1937. y J, ESSERS 2,070,221

ROTARY DRUM DRIER Filed April 23, 1936 JaKnB Ss'sers Patented Feb. 9, 1937 UNITED STATES PATENT oFFlcE signor to The Buell Combustion Company Limited, London, England, a company of Great Britain Applicationl April 23, 1936, Serial No. 75,934

'l In Germany February 7, 1935 6 Claims. (Cl. 34-6) dered or granular material to be dried. The ar-V rangements of shelves hitherto known are unsatisfactory because they permit the material that is being dried to fall practically unimpeded on to the bottom of the rotating drum. As the drying process is a surface action, if it is to be effected as efliciently as possible, the material must be caused to pass from shelf to shelf before any appreciable amount of it can reach the bot- -tom of the drum, and the object of the present invention is to achieve this result as far as possible.

According to the present invention, the interior of theA drying drum is fitted with shelves arranged in parallel units, each unit consisting of' two parallel shelves spaced apart by a connecting member in such a way that the cross-section of each unit has approximately the shape of a double L. The units are distributed over the cross-section of the drum in such a way that each shelf overlies at least one other shelf, leaving a passageway between them, and therefore the material to be dried must fall from one shelf to another during rotation of the drum.l 4

The invention will now be described more fully with reference to the accompanying diagrammatic drawing, in which:-

Figure 1 is a side elevation showing an example of a form of rotary drum drier to which the invention may be applied,

Figure 2 is'an end view of the left of Figure 1, and

Figure 3 indicates diagrammatically an enlarged cross-section of the drum with internal shelving arranged in accordance with the invention.

As shown in Figures 1 and 2 the drum l is fitted with bearing collars 2 mounted on rollers 3 which are fixed to a foundation 4. and is rotated by any convenient means. The powdered or granular material to be dried is supplied to a hopper which discharges into a conduit 6 through which heated air or other gas is caused to ilow and carry the material into the drum. The drum is tted with a packinggland l so that it can revolve around the inner end of the conduit 6 without leakage of gas. The dried material is discharged with the gas at the end 8 of the'drum. Referring now to Figure 3, each unit of the shelving consists of two parallel shelves a, b joined together by a connecting member c so that shelves a, b.

the cross-section of the unit has approximately the shape of a double L. It will be observed that the units are arranged parallel to one another and extend over the cross-section of the drum.

The dotted lines indicate approximately the manner in which the material to be dried passes from one unit to another when the drum rotates in the direction of the arrow A. When the drum is in the position indicated, there will be a layer 10 of material on the shelf b of the Unit I, and, as the drum continues to turn, this material falls onto the surface d which forms part of the shelf .b of the Unit II. The surface d, however, is not sufficiently wide to retain all the material that 15 falls on to it, and the excess material drops on to the shelf a of the Unit III which is now at such an inclination that the material slides off it on to the surface d of the Unit IV and increases the quantity of material on this surface d by the same amount that has previously dropped off it. The drum now reaches such a position that the material lies in a thin uniform layer on the connecting member c of each unit, and after a further quarter of 'a revolution the material again starts passing from one unit to another in the manner already described.

Shelves such as those marked e are supported on members f which are secured to the curved surface of the drum. The members e and f are so arranged that they tend to preserve to some extent the effect of the shelf units proper.

In order to ensure the proper operation of the arrangement when it is employed for drying fine grained materials, guide plates may be provided as indicated at g for the purpose of ensuring that the material follows the desired path during the rotation of the drum. It will be appreciated that the connecting member c of each unit need not be arranged exactly at right angles to the It' will be appreciated that in order to cause the material to travel from one end of the drum to the other, it is necessary either to incline the drum slightly, so that the discharge end is at a lower level than the inlet end, or else to arrange that each shelf slopes slightly downwards towards the discharge end.

I claim:-

l. Apparatus for drying loose materials comprising a rotatable drum the interior of which is fitted with shelves arranged in substantially parallel units spaced apart from one another, each of a multiplicity of said units comprising two mutually overlapping end-shelves disposed 55 in substantially parallel staggered relationship and a connecting member which extends between the two at substantially right angles thereto so as to space them apart, said end-shelves and said connecting member being so arranged that the connecting member divides each of the two endshelves unequally in such a way that the wider portion of one end-shelf lies opposite the narrower portion of the other end-shelf of the unit, said units being so arranged one with respect to the other that material to be dried may traverse substantially the entire cross-section of the drum by passing from unit to unit during the rotation of the drum.

2. Apparatus for drying loose materials comprising a rotatable drum the interior of which is tted with shelves arranged in substantially parallel units spaced apart from one another, each of a multiplicity of said units comprising two mutually overlapping end-shelves disposed in substantially parallel staggered relationship and a. connecting member which extends between the two at substantially right angles thereto so as to space them apart, said end-shelves and said connecting member being so arranged that the connecting member divides each of the two endshelves unequally in such a way that the wider portion of one end-shelf `lies opposite the narrower portion of the other end-shelf of the unit, and said units being so arranged one with respect to the other that an end-shelf of one unit overlaps and is staggered relatively to an endshelf of at least one other unit and that material to be dried may traverse substantially the entire cross-section of the drum by passing from unit to unit during the rotation of the drum.

3. Apparatus for drying loose materials comprising a rotatable drum and shelf units extending generally axially of said drum, each of a multiplicity of said units being spaced from the periphery of said drum and from the other units and comprising apair of generally parallel endslselves and a connecting shelf extending between the same, one of said end-shelves extending a smaller distance at one side of said connecting shelf and a larger distance at the other side thereof and the other of said end-shelves extending a larger distance at said one side of said connecting shelf and a smaller distance at said other side thereof, each of said end-shelves being spaced from all other shelves except the connecting shelf of its unit, and said units being so arranged one with respect to the other that material to be dried may traverse substantially the entire cross-section of the drum by passing from unit to unit during the rotation of the drum.

4. Apparatus for drying loose materials comprising a rotatable drum and shelf units extending generally axially of said' drum, each of a multiplicity of said units being spaced from the periphery of said drum and from the other units,

and comprising a pair of generally parallel end-v shelves and aconnecting shelf extending between the same, one of said end-shelves extending a smaller distance at one side of said connecting shelf and a larger distance at the other side thereof and the other of said end-shelves extending a larger distance at said one side of said connecting shelf and a smaller distance at said other side thereof, and said multiplicity of units being arranged in end-to-end series with the units of one series staggered with respect to the units of another series, and with the opposed end-shelves of two units of one series disposed intermediate the planes of the end-Shelves of a unit of an adjacent series.

5. Apparatus for dryingloose materials comprising rotatable drum and independent shelf units extending generally axially of the drum, each of a multiplicity of said units comprising a pair of end-shelves staggered with respect to each other and a connecting shelf member meeting the same between the ends thereof, the end-shelves of the variousones of said multiplicity of units being staggered in a manner similar to the staggering of the end-shelves of the other ofsaid multiplicity of units, and said multiplicity of units being arranged in end-to-end series with the units of different series in staggered relationship with the opposed end-shelves of two shelf units disposed laterally ofthe connecting shelf member of `another of said units, the length of said connecting shelf members being greater than the distance between the opposed end-shelves of the units. t

6. Apparatus for drying loose materials comprising aA rotatable drum and independent shelf units extending generally axially of the drum, each of a multiplicity of said shelf units comprising a pair of end-shelves arranged in staggered relationship to each other, and a connecting shelf member extending between the two and dividing each of said end-shelves unequally, and each of certain of said multiplicity of shelf units being so disposed that in a given position of the drum the wider portion of its upper end-shelf will be disposed in overlapping relationship directly' beneath the narrower portion of an end-shelf of a unit above the same and will terminate directly above the wider portion of the lower endshelf of a laterally disposed unit, and that the narrower portion of its lower end-shelf will be beneath the said end-shelf of said unit beside the same and will be directly above an overlapping shelf below the same.

JAKOB ESSERS. 

